Service Manual

SERVICING
53
S-304 TESTING GAS VALVE
Direct Spark Ignition (DSI) Systems
A two-stage combination redundant operator type gas valve
which provides all manual and automatic control functions
required for gas fired heating equipment is used on 14 SEER
models.
The valve provides control of main burner gas flow, pressure
regulation, and 100 percent safety shut-off.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Ensure gas valve and main gas supply are on.
2. Using a voltmeter, check from the purple and blue wires
on 1 stage gas valves and from C and M on 2 stage gas
valves for 24 volts to gas valve.
3. If 24 volts are present and no gas flows through the valve,
replace valve.
Outlet
Inlet
Outlet Pressure
Tap
Inlet Pressure
Tap
Gas Valve
On/Off
Switch
W/R 36G54-238
WHITE ROGERS MODEL 36G 2-STAGE GAS VALVE
S-305 CHECKING MAIN BURNERS
The main burners are used to provide complete combustion
of various fuels in a limited space, and transfer this heat of the
burning process to the heat exchanger.
Proper ignition, combustion, and extinction are primarily due
to burner design, orifice sizing, gas pressure, primary and
secondary air, vent and proper seating of burners.
BECKETT BURNER
WARNING
Disconnect gas and electrical power supply.
In checking main burners, look for signs of rust, oversized and
undersized carry-over ports restricted with foreign material,
etc.
S-306 CHECKING ORIFICES
A predetermined fixed gas orifice is used in all of these
furnaces. That is an orifice which has a fixed bore and
position.
A
GAS
STREAM
B